Lactobacillus reuteri (L. reuteri) is a probiotic bacteria found in the human digestive tract. This microorganism contributes to overall health by helping to break down food, absorb nutrients, and compete with harmful bacteria.
It is often incorporated into various dietary supplements and fermented foods like yogurt to support a balanced gut microbiome. Although L. reuteri is generally considered safe for most individuals, it can lead to certain unwanted effects.
Common Side Effects
When first introducing L. reuteri, some individuals may experience mild and temporary digestive discomfort. These effects can include increased stomach gas, bloating, or mild abdominal pain. Symptoms often arise as the digestive system adjusts to the new bacteria.
Changes in bowel habits, such as loose stools or temporary constipation, can also occur. While L. reuteri is used to address diarrhea, larger doses can initially cause loose stools. These adjustments are short-lived and resolve as the gut flora stabilizes.
The production of gases by the newly introduced bacteria as they ferment carbohydrates is a common reason for bloating and gas. These mild side effects diminish within a few days to a week as the gut microbiota rebalances. Drinking plenty of water can help alleviate these discomforts.
When to Seek Medical Advice
While mild digestive issues are common and temporary, certain symptoms warrant immediate medical attention. If abdominal pain, gas, or bloating become severe or persist, consult a healthcare professional.
Signs of a more serious reaction, such as an allergic response, require immediate medical attention. These can include a rash, itching, swelling, particularly of the face, tongue, or throat, severe dizziness, or difficulty breathing. Stop taking the probiotic and seek medical evaluation if these occur.
Any signs of infection, such as a persistent sore throat, fever, or chills, should be reported to a doctor. Though rare, probiotics can lead to infections. If diarrhea lasts more than two days, particularly if accompanied by a high fever, seek medical advice.
Considerations for Specific Groups
Certain populations should exercise caution or avoid L. reuteri without medical guidance due to a higher risk of adverse reactions. Individuals with compromised immune systems (e.g., chemotherapy, HIV/AIDS, or recent surgery) should consult their healthcare provider before using probiotics. There is a rare risk of bacteria entering the bloodstream (bacteremia) in these individuals.
Individuals with serious medical conditions, including short bowel syndrome or severe acute pancreatitis, should seek professional advice. Alterations to the digestive tract in these conditions mean introducing new bacteria could lead to complications. Those with damaged heart valves should discuss probiotic use with their doctor, as there is a very rare risk of heart lining infection.
While L. reuteri is generally safe for infants and children (used for conditions like colic), parents should consult a pediatrician before administering it to premature infants or for extended periods. Pregnant and breastfeeding individuals are generally safe to use L. reuteri, but medical consultation is still recommended for personalized advice.